The dependence of myocardial ultrasonic integrated backscatter on contractile performance

Isovolumetric elasticity alteration in the human heart detected by in vivo time-harmonic elastography

Time harmonic elastography (THE) has recently been introduced for measurement of the periodic alteration in myocardial shear modulus based on externally induced low-frequency acoustic vibrations produced by a loudspeaker. In this study, we propose further developments of cardiac THE toward a clinical modality including integration of the vibration source into the patient bed and automated parameter extraction from harmonic shear wave amplitudes, wall motion profiles and synchronized electrocardiographic records. This method has enabled us to evaluate the delay between wall motion and wave amplitude alteration for the measurement of isovolumetric times of elasticity alteration during contraction (τ(C)) and relaxation (τ(R)) in a group of 32 healthy volunteers. On average, the wave amplitudes changed between systole and diastole by a factor of 1.7 ± 0.3, with a τ(C) of 137 ± 61 ms and a τ(R) of 68 ± 73 ms, which agrees with results obtained with the more time-consuming and expensive cardiac magnetic resonance elastography. Furthermore, because of the high sampling rate, elasto-morphometric parameters such as transition times and the area of wave amplitude-cardiac motion cycles can be processed in an automated way for the future clinical detection of myocardial relaxation abnormalities.

Bayesian parameter estimation for characterizing the cyclic variation of echocardiographic backscatter to assess the hearts of asymptomatic type 2 diabetes mellitus subjects

Previous studies have shown that effective quantification of the cyclic variation of myocardial ultrasonic backscatter over the heart cycle might provide a non-invasive technique for identifying the early onset of cardiac abnormalities. These studies have demonstrated the potential for measurements of the magnitude and time delay of cyclic variation for identifying early onset of disease. The goal of this study was to extend this approach by extracting additional parameters characterizing the cyclic variation in an effort to better assess subtle changes in myocardial properties in asymptomatic subjects with type 2 diabetes. Echocardiographic images were obtained on a total of 43 age-matched normal control subjects and 100 type 2 diabetics. Cyclic variation data were generated by measuring the average level of ultrasonic backscatter over the heart cycle within a region of interest placed in the posterior wall of the left ventricle. Cyclic variation waveforms were modeled as piecewise linear functions, and quantified using a novel Bayesian parameter estimation method. Magnitude, rise time and slew rate parameters were extracted from models of the data. The ability of each of these parameters to distinguish between normal and type 2 diabetic subjects, and between subjects grouped by glycated hemoglobin (HbA1c) was compared. Results suggest a significant improvement in using measurements of the rise time and slew rate parameters of cyclic variation to differentiate (P < 0.001) the hearts of patients segregated based on widely employed indices of diabetic control compared to differentiation based on the magnitude of cyclic variation.

Acoustic microscopy analyses to determine good vs. failed tissue engineered oral mucosa under normal or thermally stressed culture conditions

This study uses scanning acoustic microscopy (SAM) ultrasonic profilometry to determine acceptable vs. failed tissue engineered oral mucosa. Specifically, ex vivo-produced oral mucosal equivalents (EVPOMEs) under normal or thermally stressed culture conditions were scanned with the SAM operator blinded to the culture conditions. As seeded cells proliferate, they fill in and smooth out the surface irregularities; they then stratify and produce a keratinized protective upper layer. Some of these transformations could alter backscatter of ultrasonic signals and in the case of the thermally stressed cells, produce backscatter similar to an unseeded device. If non-invasive ultrasonic monitoring could be developed, then tissue cultivation could be adjusted to measure biological variations in the stratified surface. To create an EVPOME device, oral mucosa keratinocytes were seeded onto acellular cadaveric dermis. Two sets of EVPOMEs were cultured: one at physiological temperature 37 °C and the other at 43 °C. The specimens were imaged with SAM consisting of a single-element transducer: 61 MHz center frequency, 32 MHz bandwidth, 1.52 f#. Profilometry for the stressed and unseeded specimens showed higher surface irregularities compared to unstressed specimens. Elevated thermal stress retards cellular differentiation, increasing root mean square values; these results show that SAM can potentially monitor cell/tissue development.

Echocardiographic tissue characterization demonstrates differences in the left and right sides of the ventricular septum

The left and right ventricular function of the heart are influenced by the complex structure of the ventricular septum. The cyclic variation of ultrasonic backscatter over the cardiac cycle is known to be sensitive to both structural and functional characteristics of the myocardium. The objective of this study was to investigate differences in the measured magnitude and normalized delay of cyclic variation between the left and right sides of the ventricular septum in normal adult subjects (N = 31). The measured mean magnitudes of cyclic variation were found to be 4.9 ± 0.4 dB and 2.4 ± 0.3 dB (mean ± SE; p < 0.0001) and the corresponding normalized delay values were found to be 0.94 ± 0.05 and 1.59 ± 0.12 (mean ± SE; p < 0.0001) for the left and right sides, respectively. These results show significant differences in the measured magnitude and normalized delay of cyclic variation between the left and right sides of the ventricular septum in normal subjects that appear consistent with predictions based on previously described models of cyclic variation of backscatter and reported measurements of transmural differences in strain properties of the septum.

Early myocardial dysfunction after chronic use of anabolic androgenic steroids: combined pulsed-wave tissue Doppler imaging and ultrasonic integrated backscatter cyclic variations analysis

BACKGROUND

The chronic consumption of androgenic anabolic steroids (AAS) has shown to cause subclinical impairment of myocardial function. Pulsed-wave Doppler tissue imaging (PWDTI) detects early regional alterations of ventricular function, whereas integrated backscatter cyclic variations (IBScv) are tightly related to the contractile efficiency of the left ventricular wall. The aim of this study was to identify the effects of chronic AAS misuse on myocardial function using both PWDTI and IBScv.

METHODS

Twenty-eight male bodybuilders (11 AAS users, 17 AAS nonusers) and 20 healthy sedentary subjects (controls), matched according to age, were studied. To assess left ventricular function, each subject underwent standard Doppler echocardiography, PWDTI, and IBScv analyses.

RESULTS

Left ventricular mass was significantly higher in AAS users than in AAS nonusers and controls. Global systolic function (assessed by determining the ejection fraction) was similar in all subjects, but isovolumetric relaxation time was significantly higher in AAS users than in controls. On PWDTI analysis, AAS users showed regional systolic and diastolic dysfunction (evaluated by measuring s', e', and a') not detectable in the other two groups. IBScv identified regional systolic impairment only in AAS users at the level of the left ventricular inferior wall.

CONCLUSIONS

The present study confirms that in AAS users, PWDTI and IBScv are effective and reliable noninvasive diagnostic tools for detecting early abnormalities of the systolic and diastolic longitudinal myocardial function, probably related to an increase in myocardial collagen content, interpretable as a repair process against the direct cellular injury produced by AAS.

Cardiovascular complications in patients with pheochromocytoma: a mini-review

Phaeochromocytomas are rare neuroendocrine tumours secreting high levels of catecholamines, able to exert serious metabolic and cardiovascular effects. The serious and potentially lethal cardiovascular complications of these tumours are due to the potent effects of secreted catecholamines, especially noradrenaline, the main transmitter released from sympathetic nerve terminals. Hypertension, tachycardia, pallor, headache and anxiety, usually dominate the clinical presentation. Occasionally, patients with predominantly epinephrine-secreting tumours present hypotension or even shock. Other cardiovascular complications of pheochromocytoma include ischaemic heart disease, acute myocardial infarction, cardiac arrhythmias, heart failure due to toxic cardiomyopathy, or pulmonary edema. Catecholamines have been shown to influence the extracellular matrix with collagen deposition and subsequent fibrosis in the arterial wall and in the myocardium. These morphofunctional changes of the myocardium and of arterial wall can be emphasized by ultrasound imaging. Indeed, ultrasound imaging of the myocardium and arterial wall not only identifies wall thickness but also contains information on texture that may be revealed by acoustic tissue characterization. The latter can be quantified through videodensitometric analysis of echographic images or through ultrasonic integrated backscatter signal analysis. This paper reviews cardiovascular complications in patients with pheochromocytoma and utility of the new ultrasound technique as backscatter signal. It is useful for evaluating preclinical pathological morphofunctional changes of the myocardium and arterial wall, characterized by increased collagen content in pheochromocytoma patients. The recognition of early catecholamine-induced alterations in patients with pheochromocytoma, is important to prevent at least morbidity and mortality, before surgical treatment.

Effect of cibenzoline on regional left ventricular function in hypertrophic obstructive cardiomyopathy

BACKGROUND

Cibenzoline, a class Ia antiarrhythmic drug, can be used to relieve left ventricular (LV) outflow obstruction in hypertrophic obstructive cardiomyopathy (HOCM). However, the mechanism of this agent in HOCM has been controversial.

HYPOTHESIS

This study was designed to investigate the effect of cibenzoline on regional LV function and the acoustic properties in HOCM using ultrasonic integrated backscatter.

METHODS

Ten patients with HOCM and 16 healthy volunteers were examined. In patients with HOCM, wall thickening (%WT) and the magnitude of cyclic variation of integrated backscatter (mag-CVIBS) in the interventricular septum (IVS) and LV posterior wall were measured before and after oral administration of cibenzoline. To assess asynchrony of contractile elements, the phase difference between CVIBS and %WT were measured from the LV posterior wall. Pressure gradients at the LV outflow tract were estimated using continuous-wave Doppler echocardiography.

RESULTS

Although %WT decreased significantly in the LV posterior wall, %WT and mag-CVIBS remained unchanged in the IVS. The phase difference in the LV posterior wall was significantly greater in patients with HOCM than in healthy volunteers (HOCM:healthy volunteers, 1.57 +/- 0.23:1.00 +/- 0.03, p < 0.001) at baseline. After administration of cibenzoline, the phase difference shifted to normal value (from 1.57 +/- 0.23 to 1.28 +/- 0.27, p = 0.0382), and pressure gradients at the LV outflow tract decreased (from 109 +/- 55 to 58 +/- 48 mmHg, p = 0.0063). Changes in pressure gradients at the LV outflow tract and the phase difference were closely related.

CONCLUSIONS

Regional function and the acoustic properties of myocardium in HOCM were altered by cibenzoline in the LV posterior wall but remained unchanged in the IVS. The normalization of the phase difference in the LV posterior wall was closely related to the decrease in pressure gradients at the LV outflow tract. These findings suggest that negative inotropic action and the improvement of asynchrony in the LV posterior wall rather than in the IVS may contribute to the reduction of pressure gradients at the LV outflow tract in HOCM.

Preclinical cardiac involvement in phaeochromocytoma: a study with integrated backscatter

OBJECTIVE

It is well known that vascular and cardiac structure may be influenced by circulating neurohormonal factors. Our aim was to study the myocardial wall texture by integrated backscatter (IBS) analysis in patients with phaeochromocytoma (PHEO).

DESIGN

Fourteen patients with PHEO, 15 matched high-normal blood pressure (BP) subjects, 15 mild essential hypertensives and 15 normotensive controls underwent two-dimensional conventional ultrasonography and ultrasonic IBS of the myocardial wall. IBS analysis was performed at both interventricular septum and posterior wall levels. IBS values were expressed in decibels and corrected for the IBS values obtained within the pericardium (C-IBS). The systo-diastolic cyclical variations in IBS (CV-IBS), an index of myocardial contractile performance, were also evaluated.

RESULTS

Patients with PHEO showed C-IBS values comparable to those of hypertensive patients, and significantly higher than those of high-normal BP subjects and controls at both septum and posterior wall levels (P < 0.001 for all). In PHEO patients, CV-IBS was lower than that of normotensive, high-normal BP subjects and hypertensive patients, at both septum and posterior wall levels (P < 0.001 for all). An inverse relationship was found in the PHEO group between 24-h urinary normetanephrine and CV-IBS of both septum (r(2) = -0.29, P < 0.05) and posterior wall (r(2) = -0.46, P < 0.05).

CONCLUSIONS

Our results show that patients with PHEO have myocardial remodelling characterized by increased myocardial fibrosis, confirmed by an increase in the overall myocardial backscatter level measured. The observed decrease in the magnitude of CV-IBS suggests an impairment of myocardial contractile performance. These results may provide insights into the role of catecholamines in left ventricular (LV) structure and function in PHEO.

Effect of preload reduction on sonographic myocardial integrated backscatter

PURPOSE

Sonographic myocardial tissue characterization with integrated backscatter (IBS) is affected by both structural and functional properties of the myocardium. The aim of the present study was to investigate the effect of preload reduction by hemodialysis (HD) on IBS measurements.

METHODS

Fifty-two patients on maintenance HD underwent echocardiography before and after a routine HD session. Measurements included the variation of IBS during the cardiac cycle (CV-IBS) and calibrated IBS (cal-IBS).

RESULTS

After HD, there were significant reductions in left ventricular end-diastolic and end-systolic dimensions and left atrial diameter. There was a reduction in stroke volume and LV ejection fraction consistent with a reduction in preload. Furthermore, CV-IBS was significantly lower after HD (7.9 +/- 2.2 versus 6.9 +/- 1.8 dB, 7.0 +/- 2.1 versus 6.2 +/- 1.9 dB, and 9.0 +/- 2.6 versus 8.1 +/- 2.0 dB [p < 0.01], respectively, in the left anterior, lateral, and inferior wall of the ventricle). Cal-IBS remained unchanged after dialysis compared with baseline. CV-IBS and ultrafiltration volume were significantly correlated.

CONCLUSION

HD leads to a decrease in CV-IBS that appears to be preload-dependent. This finding is in concordance with diminished left ventricular performance during HD.

Myocardial Texture in Hypertrophic Cardiomyopathy

BACKGROUND

This study was conceived to assess associations between integrated backscatter signal at end diastole (IBS) and diastolic properties in patients with hypertrophic cardiomyopathy.

METHODS

In 46 patients with hypertrophic cardiomyopathy, septal IBS was calculated by both applying an appropriate regression correction (IBSc) and by relating it to pericardial reflectivity (IBSp). Difference in duration between transmitral forward and pulmonary venous backward velocities (A-Ar) was measured as an estimate of passive diastolic filling. In all, 38 patients underwent ambulatory electrocardiogram monitoring for 48 hours.

RESULTS

IBS inversely correlated to both A-Ar (IBSc, r = -.522, P < .001; IBSp, r = -.302, P = .041) and mitral peak velocity at atrial contraction (IBSc, r = -.464, P = .002; IBSp, r = -.413, P = .004). Moreover, IBS was greater in patients with sustained or nonsustained ventricular tachycardia (IBSc, 28.5 +/- 3.8 vs 25.4 +/- 3.8 dB, P = .034).

CONCLUSIONS

Septal IBS correlates with Doppler parameters of left ventricular chamber stiffness in patients with hypertrophic cardiomyopathy. Increased IBS is associated with presence of ventricular arrhythmias.

Assessment of the relationship between functional capacity and right ventricular ultrasound tissue characterization by integrated backscatter in patients with isolated mitral stenosis

AIM

The aim of the present study was to investigate right ventricular (RV) myocardial textural properties in asymptomatic and symptomatic mitral stenosis (MS) patients with normal RV systolic function using integrated backscatter (IBS).

METHODS

The study included 40 patients with MS of moderate or severe degree. Patients were classified into 2 groups according to NYHA class (asymptomatic group, NYHA class I, symptomatic group, NYHA class II-III). RV pulsed-wave tissue Doppler imaging (TDI) and IBS analyses were performed in all patients. Isovolumic contraction time (IVCT), systolic wave velocity (S), isovolumic relaxation time (IVRT), early diastolic wave velocity (E), and late diastolic wave velocity (A) were measured by TDI. IBS amplitude (IB) and cyclic variation (CV) of the RV lateral wall in the parasternal long-axis view were measured by IBS. CV was calculated by subtracting systolic IB from diastolic IB.

RESULTS

IVRT (54.2 +/- 11.9 ms versus 86.2 +/- 16.2 ms, P < 0.001) and A wave amplitude (10.2 +/- 2.1 cm/s versus 13.6 +/- 1.8 cm/s, P < 0.05) were higher whereas E wave amplitude (11.7 +/- 1.6 cm/s and 10.3 +/- 1.5 cm/s, P < 0.05) and E/A ratio (1.3 +/- 0.3 versus 0.7 +/- 0.1, P < 0.001) were lower in group 2. Symptomatic patients had a lower CV value of RV (9.5 +/- 3.4 dB versus 6.7 +/- 1.9 dB, P = 0.004). There was a positive correlation between CV and E/A (r = 0.964, P < 0.001)

CONCLUSION

Symptomatic isolated MS patients had RV echo texture changes and diastolic dysfunction in comparison to asymptomatic ones with similar mitral valve areas in the presence of normal RV systolic function. In isolated MS, both pulsed-wave TDI and IBS may aid in the detection of RV diastolic pathology.

Left ventricle myocardial mechanics and textural properties in patients with Williams syndrome

OBJECTIVE

To study left ventricular mechanics and textural properties in patients with Williams syndrome to define the impact of left ventricular hypertrophy on the functional findings.

METHODS

Echocardiography was performed in 16 Williams syndrome patients (aged 1-25 years, mean 10 +/- 6 years), four with associated supravalvular aortic stenosis and seven with systemic hypertension. Fifteen age- and body surface area-matched subjects were selected as control group. Particularly, left ventricular geometry, myocardial contractility [midwall rate-corrected circumferential fiber shortening/end-systolic meridional wall stress relationship (sigmaes)] and left ventricular diastolic function (mitral flow pattern and isovolumic relaxation time) were defined. In addition, integrated backscatter (IB) analysis intensity (IntIB) and cyclic variation (CVIB) were assessed for an ultrasonic myocardial characterization.

RESULTS

Left ventricular hypertrophy was demonstrated in nine patients (56%) and abnormal left ventricular remodeling in ten patients (62%). Particularly seven of seven hypertensive patients and three of four patients with supravalvular aortic stenosis had abnormal remodeling; left ventricular geometry was normal in patients without hypertension or supravalvular aortic stenosis. In addition, midwall rate-corrected circumferential fiber shortening/(sigmaes) relationship was within the normal range in all patients. At integrated backscatter analysis, Williams syndrome patients showed, both at interventricular septum and posterior wall, reduced CVIB (9.36 +/- 2.16 versus 10.3 +/- 1.3 and 8.65 +/- 2 versus 10.5 +/- 1.1). Compared to Williams syndrome patients without left ventricular hypertrophy (7/16), those with left ventricular hypertrophy (9/16) showed decreased mitral E/A ratio (1.32 +/- 0.09 versus 1.62 +/- 0.02), increased isovolumic relaxation time (68 +/- 7 versus 53 +/- 7) and increased IntIBS at interventricular septum (-27.3 +/- 0.07 versus -34 +/- 5).

CONCLUSIONS

Our data obtained in young Williams syndrome patients show that: (i) mild left ventricular functional and textural abnormalities may be detected also in absence of significant supravalvular aortic stenosis and/or hypertension; (ii) significant left ventricular hypertrophy may develop since childhood; (iii) differences in left ventricular remodeling and/or degree of left ventricular hypertrophy may occur. Further studies are required to define the real impact of the functional abnormalities on the natural history in patients with Williams syndrome.

Cyclic variation in ultrasonic myocardial integrated backscatter is due to phasic changes in the number of patent myocardial microvessels

OBJECTIVE

We tested the hypothesis that the cyclic variation in ultrasonic myocardial integrated backscatter (IBS) is due to cardiac contraction-induced changes in the number of patent myocardial microvessels.

METHODS

We performed experiments in open-chest dogs in which we increased the number of patent myocardial microvessels without changing cardiac contraction. We achieved this either by direct intracoronary administration of adenosine (group 1; n = 10) or by producing a noncritical coronary stenosis (group 2; n = 7).

RESULTS

At baseline, IBS was lowest in systole and highest in diastole. This cyclic variation in IBS was closely associated with the phasic changes in myocardial blood volume that were measured with myocardial contrast echocardiography. During adenosine administration, the diastolic IBS increased from -18.8 +/- 6.5 to -17.5 +/- 6.1 dB (P = .002), with an associated increase in the difference between the systolic and diastolic IBS from 3.8 +/- 1.1 to 4.6 +/- 1.0 dB (P = .009). After a noncritical stenosis was produced, diastolic IBS also increased from -26.6 +/- 8.3 to -25.2 +/- 7.3 dB (P = .001), with an associated increase in the difference between the systolic and diastolic IBS from 3.7 +/- 1.2 to 5.0 +/- 1.0 dB (P = .02). No change in IBS was noted in the bed that did not receive adenosine or the bed that had a stenosis.

CONCLUSIONS

The variation in IBS during the cardiac cycle is closely associated with the phasic changes in myocardial blood volume seen during cardiac contraction. When the number of patent myocardial arterioles is increased via adenosine or placement of a noncritical stenosis, diastolic IBS increases with a concomitant increase in IBS cyclic variation. These results may have important clinical applications for the noninvasive diagnosis of noncritical coronary stenosis at rest.

Impact of the angiotensin II receptor antagonist, losartan, on myocardial fibrosis in patients with end-stage renal disease: assessment by ultrasonic integrated backscatter and biochemical markers

Myocardial fibrosis commonly occurs in patients with end-stage renal disease (ESRD) and has proven to be an important predictor for cardiovascular events. In experimental settings, angiotensin II type 1 receptor (AT1-R) antagonists have been shown to have anti-fibrotic effects on the myocardium independent of their antihypertensive effects. In this study, to investigate whether the AT1-R antagonist losartan would have such anti-fibrotic effects in patients, we administered losartan or, for purpose of comparison, the angiotensin-converting enzyme enalapril or Ca2+-antagonist amlodipine to patients with ESRD. Thirty-nine ESRD patients with hypertension were randomly assigned to receive losartan (n=13), enalapril (n=13), or amlodipine (n=13). Ultrasonic integrated backscatter (IBS) and serological markers of collagen type I synthesis and degradation were used to assess the degree of myocardial fibrosis just before and after 6 months of treatment. There were no significant differences in antihypertensive effects among the three agents. In the enalapril- and amlodipine-treated groups, the mean calibrated IBS values increased significantly after 6 months of treatment (enalapril: -31.6 +/- 1.3 to -29.4 +/- 1.2 dB, p=0.011; amlodipine: -30.6 +/- 1.4 to -27.2 +/- 1.2 dB, p=0.012). However, the mean calibrated IBS values in the losartan-treated group did not increase after 6 months of treatment (-31.2 +/- 1.7 to -31.3 +/- 1.4 dB, p=0.88). The ratio of the serum concentration of procollagen type I carboxy-terminal peptide to the serum concentration of collagen type I pyridinoline cross-linked carboxy-terminal telopeptide was significantly reduced in the losartan-treated group (42.6 +/- 4.6 to 34.4 +/- 3.6, p=0.038). The present study indicates that losartan more effectively suppresses myocardial fibrosis in patients with ESRD than does enalapril or amlodipine despite a comparable antihypertensive effect among the three drugs.

Detection of cardiac sarcoidosis using cardiac markers and myocardial integrated backscatter

BACKGROUND

It is not known whether cardiac markers and cyclic variations of integrated backscatter can be used to detect cardiac sarcoidosis.

METHODS

We studied 62 patients with sarcoidosis affecting the lung, eyes, skin, or heart (27 patients with cardiac involvement and 35 patients without). The cyclic variation of integrated backscatter and wall thickening was evaluated in the left ventricular anterior septum and posterior wall. Plasma A-type natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) concentrations and serum cardiac troponin T were also determined.

RESULTS

Plasma natriuretic peptide concentrations were higher in the cardiac involvement group (ANP: 15.5 [interquartile range (IQR) 2.5-34.0] vs. 12.0 [10.0-16.5] pg/ml, P=0.25; BNP: 28.6 [5.9-141] vs. 10.1 [4.8-15.4] pg/ml, P=0.049). However, cardiac troponin T concentration was <0.01 ng/ml in all patients. Receiver-operator characteristic (ROC) analysis showed that both ANP and BNP could identify patients with high-degree atrioventricular block, ventricular tachyarrhythmias, or symptomatic heart failure (the areas under the ROC curve were 0.94 and 0.97, respectively). The cardiac involvement group could be distinguished from the noninvolvement group by combining cutoff values for the magnitude of integrated backscatter cyclic variation (5.5 dB) and wall thickening (30%), albeit only for the posterior wall.

CONCLUSION

Both ANP and BNP are useful markers for identifying patients with sarcoidosis and cardiac complication(s). Moreover, evaluation of integrated backscatter cyclic variation combined with wall thickening may be of help in detecting cardiac involvement in the posterior wall.

Left ventricular function and calcium phosphate plasma levels in uraemic patients

BACKGROUND. Recent investigations have focused on the pathogenetic role of disturbances of calcium phosphate metabolism in causing cardiovascular morbidity and mortality in haemodialysis patients. The aim of the present study was to assess left ventricular function and its relationship to phosphate and calcium plasma levels in stable uraemic patients on haemodialysis treatment.

METHODS

Twenty uraemic patients (mean age 51+/-13 years) on maintenance haemodialysis and free from overt cardiac dysfunction, and 20 healthy volunteers underwent standard echocardiography, tissue Doppler-derived early (E(m)) and late (A(m)) diastolic velocities, tissue characterization with cyclic variations of integrated backscatter (CV-IBS), and serum biochemistry.

RESULTS

With respect to tissue Doppler imaging (TDI), uraemic patients showed a lower E(m) peak, a higher A(m) peak, and a reduced E(m)/A(m) ratio of both interventricular septum and lateral wall (0.01>P<0.001) than controls. CV-IBS of both septum and posterior wall was significantly smaller in uraemic patients than in the control subjects (P<0.001). Moreover, the E(m)/A(m) ratio of septum and lateral wall were negatively related to serum phosphorus and to calcium phosphate product (P<0.001 for all). Accordingly, an inverse relationship was also found between CV-IBS of septum and lateral wall and calcium phosphate product and phosphorus (P<0.05 for all).

CONCLUSIONS

These results showed early cardiac impairment of diastolic myocardial function evaluated by TDI and IBS analysis, and a close relationship between these changes and the calcium-phosphate plasma levels. These findings are well in keeping with the important role of hyperphosphataemia as a risk factor for cardiovascular damage, and justify the effort for optimal control of calcium phosphate metabolism in uraemic patients.

Changes in cardiac tissue characterization in carriers with gene mutations associated with hypertrophic cardiomyopathy

BACKGROUND

Early detection in patients with hypertrophic cardiomyopathy (HCM) is very important. Integrated backscatter (IB) provides a useful noninvasive measure of the acoustic properties of the myocardium, and may detect early myocardial changes.

METHODS

Thirty-four carriers who had gene mutations causing HCM were studied. The patients were divided into three groups as follows: (1) 21 patients with wall hypertrophy (Group A), (2) 7 patients with ECG abnormalities but without wall hypertrophy (Group B), and (3) 6 carriers with neither ECG abnormalities nor wall hypertrophy (Group C). All subjects underwent ECG, conventional echocardiography and acoustic densitometry. In addition, we studied subjects < or =20 years old from Groups B and C (Group B-2 and Group C-2, respectively), and compared them with control subjects with no cardiac disorders who were < or =20 years old.

RESULTS

In Group A, cyclic variations of integrated backscatter (CV-IB) in the interventricular septum and left ventricular posterior wall were significantly smaller than in Group C. The amplitude of IB in the interventricular septum and left ventricular posterior wall in Group A was significantly higher than those in Group C. Even in Group B, CV-IB in the interventricular septum was significantly smaller than those in Group C. Among patients < or =20 years old, CV-IB in the interventricular septum was significantly smaller in Group B-2 than in control subjects, while that in Group C-2 did not differ from that in control subjects.

CONCLUSIONS

Changes in tissue characterization were found in the hearts of HCM gene carriers even in the absence of wall hypertrophy. These results suggest that tissue changes detectable by the acoustic densitometry methods may occur in the hearts of HCM gene carriers without wall hypertrophy, and that they may be detectable at the time of appearance of ECG abnormalities.

The use of collagen-derived serum peptides for the clinical assessment of hypertensive heart disease

Given the importance of fibrous tissue in leading to myocardial dysfunction and failure in hypertensive heart disease, non-invasive assessment of fibrosis could prove a clinically useful tool in hypertensive patients, particularly given the potential for cardioprotective and cardioreparative pharmacological strategies. In this regard, an emerging experimental and clinical experience holds promise for the assessment of various serum peptides arising from the metabolism of collagen types I and III in arterial hypertension. More specifically, the measurement of serum concentrations of procollagen type I carboxy-terminal propeptide (a peptide that is cleaved from procollagen type I during the synthesis of fibril-forming collagen type I) may provide indirect diagnostic information on both the extent of myocardial fibrosis and the ability of antihypertensive treatment to diminish collagen type I synthesis and reduce myocardial fibrosis in hypertensive patients. The available data set the stage for large and long-term trials to definitively validate this approach.

Subclinical cardiac involvement in patients with facioscapulohumeral muscular dystrophy

Myocardial involvement is a common finding in certain myopathies, while it has not been extensively investigated in facioscapulohumeral muscular dystrophy (FSHD1A). Aim of this study was to assess in FSHD1A patients the electrical and functional properties of the myocardium. Twenty-four patients with FSHD1A (mean age 41.2+/-14.5 years) and 24 matched healthy subjects were studied. Standard- and signal-averaged electrocardiography were recorded to determine QT dispersion and the presence of ventricular late potentials (VLPs). Standard echocardiography with systo-diastolic variations of integrated backscatter signal (CV-IBS) were performed to assess functional properties of the myocardium. Compared with control subjects, patients with FSHD1A had significantly lower CV-IBS and higher QT dispersion. Nine patients had positive VLPs. QT and QTc dispersion were inversely related to CV-IBS at both septum and posterior wall levels. Moreover, septal CV-IBS was inversely related to the Kpnl-BinI4q fragment size. These results suggest a subclinical cardiac involvement in FSHD1A patients, which can represent a substrate for ventricular arrhythmias and heart failure.

The influence of growth hormone therapy on ultrasound myocardial tissue characterization in patients with childhood onset GH deficiency

BACKGROUND

In growth hormone deficiency (GHD), a reduction in left ventricular mass (LV-mass) and impairment of systolic function has been shown. In this study, we investigated the effects of 12 months of GH replacement therapy on cardiac structure and functional indices measured by echocardiographic techniques in adult patients with childhood onset GH deficiency.

METHODS

Sixteen patients (age 42.3+/-13.1 years, 10 males) were investigated before and after 12 months of GH treatment at a dose of 0.02 IU/kg/day (7 microg/kg/day). Echocardiography was performed including the ultrasound myocardial tissue characterization technique. We measured two parameters of the ultrasonic tissue characterization with integrated backscatter: the magnitude of the cardiac-cycle-dependent variation in integrated backscatter signals (CV-IBS) and the mean value of integrated backscatter signals calibrated by the pericardium (cal-IBS).

RESULTS

Left ventricular diameter and wall thickness did not change after GH treatment, although systolic increase in interventricular septum thickness (IVS%) and systolic increase in posterior wall thickness (PWT%) increased significantly (IVS% 52.2+/-31.9% vs. 67.3+/-30.4% and PWT% 48.7+/-20.2% vs. 58.0+/-17.7%, p<0.01 and p<0.01, respectively). Ejection fraction increased from 56.2+/-7.2% to 63.2+/-6.1% (p<0.01). LV-mass index did not change after GH treatment (78.4+/-22.1 vs. 81.9+/-21.1 g/m(2)). CV-IBS increased significantly after GH treatment (p<0.05), in both the interventricular septum and the left ventricular posterior wall (4.7+/-1.5 vs. 5.8+/-1.9 dB for the interventricular septum, 4.9+/-1.8 vs. 6.5+/-2.4 dB for the left ventricular posterior wall, p<0.05 and p<0.05, respectively). Cal-IBS also increased significantly after GH treatment (-23.5+/-4.1 vs.-21.8+/-4.2 dB for the interventricular septum, -23.0+/-4.4 vs. -21.8+/-4.3 dB for the left ventricular posterior wall, p<0.01 and p<0.05, respectively).

CONCLUSION

Twelve months GH treatment in adults with childhood onset GHD resulted in improvement of cardiac contractile performance. Observed changes in cal-IBS and CV-IBS suggest that GH treatment in this patient group can lead to a further somatic maturation of the heart, probably not accomplished previously.

Ultrasound Tissue Characterization by Integrated Backscatter for Analyzing Fluorouracil Induced Myocardial Damage

BACKGROUND

5-Fluorouracil (5-FU) cardiotoxicity is a well-known clinical phenomenon whose pathophysiology remains controversial. Cyclic variation of integrated backscatter (CVIBS) assesses acoustic properties of myocardium that may reflect both contractility and structural changes. The aim of this study was to evaluate CVIBS alterations in cancer patients under high-dose leucovorin and infusional 5-FU (HDLV5FU) chemotherapy.

METHOD

We prospectively evaluated 37 cancer patients under HDLV5FU treatment. Transthoracic echocardiography and CVIBS were performed at the 0th, 48th hours, and on day 15 of the first cycle. The parasternal long-axis view was preferred to obtain the image of integrated backscatter and mainly two regions of interest--interventricular septum (IVS) and posterior wall (PW)--were used.

RESULTS

Clinical cardiotoxicity was observed in two patients. No significant differences were detected in pre- and posttreatment conventional echocardiography evaluations. However, both the IVS (9.3 +/- 1.0 to 8.1 +/- 1.2 dB, P < 0.001) and PW (9.1 +/- 0.7 to 7.8 +/- 0.9 dB, P < 0.001) CVIBS values significantly decreased in all patients. All values were returned to pretreatment levels (9.2 +/- 0.9 dB in the CVIBS-IVS and 8.9 +/- 0.6 dB in CVIBS-PW, respectively) on day 15 after the treatments.

CONCLUSION

This study suggests that HDLV5FU may cause acute transient alterations in CVIBS values in the absence of clinical symptoms and signs of cardiotoxicity. The clinical value of CVIBS should be further studied in patients receiving 5-FU-based therapy.

Early myocardial abnormalities in asymptomatic patients with severe isolated congenital aortic regurgitation: An ultrasound tissue characterization and strain rate study

BACKGROUND

Aortic valve regurgitation (AR) in the pediatric population has increased in recent years because of the expanded use of new surgical and hemodynamic procedures. Unlike adult patients, few predictors for the need of operation have been proposed in young asymptomatic or mildly symptomatic patients with AR.

METHODS

To unmask early abnormalities of left ventricular (LV) function, 59 participants were enrolled: 14 asymptomatic patients (mean age 18 years) with congenital isolated severe AR and normal LV function (LV ejection fraction > 50%); and 45 healthy control subjects with comparable age and body surface area. All the studied population underwent standard echocardiographic examination, integrated backscatter, and strain rate imaging study.

RESULTS

Conventional echocardiographic indices of global LV systolic performance for patients with AR were similar to that of control subjects. Compared with control subjects, integrated backscatter analysis demonstrated a significant reduction in cyclic variation in both septal and posterior walls ( P < .05). LV radial and longitudinal deformation properties for patients with AR were significantly reduced ( P < .05) as assessed by peak systolic strain rate.

CONCLUSION

Our results demonstrated the ability of integrated backscatter and strain rate imaging to detect early subclinical abnormalities in young patients with severe congenital AR despite the presence of a normal ejection fraction.

Early detection of cardiac involvement in patients with sarcoidosis by a non-invasive method with ultrasonic tissue characterisation

OBJECTIVES

To clarify the value of cycle dependent variation of myocardial integrated backscatter (CV-IB) analysis, which non-invasively measures acoustic properties of the myocardium, for early detection of cardiac involvement in patients with sarcoidosis.

METHODS

The study population consisted of 22 consecutive patients with biopsy proven sarcoidosis who did not have any abnormal findings on conventional two dimensional echocardiogram. Cardiac sarcoidosis was diagnosed by radionuclide testing including thallium-201 scintigraphy, gallium-67 scintigraphy, and cardiac fluorine-18-deoxyglucose positron emission tomography. The magnitude and delay of the CV-IB were analysed in the basal mid septum and the basal mid posterior wall of the left ventricle of all patients.

RESULTS

The patients were divided into two groups: 8 patients with cardiac involvement and 14 patients without cardiac involvement. In the basal septum, a major reduction in the magnitude (mean (SD) 1.8 (4.4) v 6.6 (1.3), p = 0.012) and an increase in the time delay (1.3 (0.5) v 1.0 (0.1), p = 0.038) of CV-IB were observed in patients with cardiac sarcoidosis even in the absence of two dimensional echocardiographic abnormalities. The sensitivity for detecting cardiac involvement was such that the magnitude of CV-IB in the basal septum discriminated 75% of patients with cardiac sarcoidosis from those with non-cardiac sarcoidosis, whereas two dimensional echocardiographic parameters did not discriminate between these two groups.

CONCLUSIONS

The CV-IB is decreased in the basal septum in patients with cardiac sarcoidosis even in the absence of two dimensional echocardiographic abnormalities. Analysis of CV-IB may be a useful method to detect early myocardial involvement in patients with sarcoidosis.

Potential relationships among myocardial stiffness, the measured level of myocardial backscatter (“image brightness”), and the magnitude of the systematic variation of backscatter (cyclic variation) over the heart cycle

BACKGROUND

In a number of recently published studies comparing measurements from patients with those from control subjects, a decreased magnitude of the systematic variation of backscattered energy over the heart cycle (cyclic variation) is accompanied by an increased level of overall myocardial backscatter (calibrated myocardial image brightness) when measured at a specific phase of the heart cycle (eg, end systole or end diastole). The goal of this study was to investigate whether this observation is consistent with predictions based on a model of the mechanisms of cyclic variation incorporating changes in relative intracellular and extracellular acoustic impedance over the heart cycle.

METHODS

A previously described 3-component Maxwell-type model of muscle mechanics representing cardiac cell mechanical behavior was utilized to predict the systematic variation in the relative acoustic impedance differences between intracellular and extracellular elastic properties over the heart cycle and hence the observed magnitude of cyclic variation and overall myocardial scattering level. Predictions were obtained for a series of specific values of relative intracellular and extracellular acoustic impedance.

RESULTS

Results indicate that the predicted magnitude of cyclic variation can be directly related to the overall myocardial backscatter level. For example, specific changes in the acoustic impedance (stiffness properties) of the extracellular matrix without any change in the intracellular acoustic impedance result in predicted values of -43.5 dB, -38.5 dB, and -33.5 dB for end-diastolic myocardial backscatter levels with corresponding values of 5.0 dB, 2.5 dB, and 1.3 dB for the predicted magnitude of cyclic variation, respectively.

CONCLUSION

This study suggests that observed decreases in the magnitude of cyclic variation with concomitant increases in the measured overall myocardial backscatter level are consistent with predictions from a model based on the relative acoustic impedance differences between intracellular and extracellular elastic properties over the heart cycle. These results suggest that ultrasonic backscatter measurements may provide a noninvasive approach for assessing some relationships among myocardial stiffness, degree of fibrosis, and contractile performance.

Ultrasonic tissue characterization of the mouse myocardium: Successful in vivo cyclic variation measurements

BACKGROUND

Measurements of the systematic variation of backscattered ultrasonic energy from myocardium during the heart cycle (cyclic variation) have been successfully used to characterize a wide spectrum of cardiac pathologies in large animal models and human subjects. The purpose of this study was to evaluate the feasibility of extending cyclic variation measurements to the study of genetically manipulated mouse models of cardiac diseases as a method for developing further insights into the disease-altered properties of the myocardium and its characterization with ultrasound.

METHODS

Parasternal long-axis images of the heart were obtained in 9 wild-type mice under light anesthesia using a commercial imaging system with a 15-MHz nominal center frequency linear array. Images of a tissue-mimicking phantom and the mouse hearts were obtained for a series of specific receiver gains for each of a series of specific dynamic range settings. Analyses of these data formed the basis for gray-scale image calibration. Cyclic variation measurements were obtained by determining the average gray-scale value for a region of interest placed in the midmyocardium of the posterior wall for each frame acquired during 4 cardiac cycles and converting these mean gray-scale values to backscatter values expressed in decibels using the determined calibration. Results are expressed in terms of the magnitude and time delay of cyclic variation. To evaluate repeatability of these measurements the same group of mice underwent the identical imaging protocol 2 weeks after the first study.

RESULTS

The mean magnitude of cyclic variation was found to be 4.6 +/- 0.2 dB with a corresponding normalized time delay of 1.02 +/- 0.03 for data averaged over all dynamic range settings. There was no significant difference among results obtained with each of the dynamic range settings. A comparison of these results with those from data acquired 2 weeks after the initial study showed no significant difference.

CONCLUSION

This study represents the first reported measurement of cyclic variation in mice and demonstrates that reliable cyclic variation measurements can be obtained among individual animals and over different time points and, hence, forms the basis for subsequent investigations addressing specific cardiac pathologies and effects arising from myocardial anisotropy.

Prediction of the no-reflow phenomenon with ultrasonic tissue characterization in patients with anterior wall acute myocardial infarction

The no-reflow phenomenon after acute myocardial infarction seems to be related to ischemic injury before reperfusion. Analyzing cardiac cycle-dependent variation of integrated backscatter (IBS) is a unique method to assess myocardial viability. In this study, the ability of ultrasonic tissue characterization with IBS to predict the no-reflow phenomenon was investigated in 90 patients with first anterior wall infarction who underwent successful primary percutaneous coronary intervention. IBS images were recorded on admission (before reperfusion), and the magnitude of the cyclic variation of IBS within the infarct zone was expressed as phase-corrected magnitude (PCM) by giving positive and negative values when it showed synchronous and asynchronous contraction, respectively. Myocardial contrast echocardiography was performed soon after reperfusion, and 21 patients showed substantial no-reflow. They had smaller PCM before reperfusion than patients without no-reflow (-1.6 +/- 1.9 vs 0.7 +/- 2.7 dB, respectively; p = 0.0002). Multivariate logistic regression analysis revealed that PCM before reperfusion and the number of Q waves were the independent predictors of no reflow. Using -1.0 dB as the cut-off point, PCM predicted no reflow with 66.7% sensitivity and 81.2% specificity. These results indicate that the analysis of myocardial IBS could predict the no-reflow phenomenon before reperfusion.

Myocardial ultrasound tissue characterization in patients with hypertrophic cardiomyopathy: noninvasive evidence of electrical and textural substrate for ventricular arrhythmias

BACKGROUND

Although in patients with hypertrophic cardiomyopathy (HCM) pathologic studies seem to suggest a correlation between morphologic findings and arrhythmias, it has never been confirmed in the clinical setting.

OBJECTIVE

We sought to noninvasively assess the electrical and textural properties of the myocardium and to define their potential relationship in patients with HCM.

METHODS

We studied 48 patients: 22 with HCM (mean age: 22 +/- 5.1 years) and 26 age- and body surface area-matched healthy patients. They underwent a standard echocardiographic examination to assess left ventricular size and thickness. In addition, by integrated backscatter analysis, we assessed textural properties of left ventricular myocardium with calibrated averaged intensity (IB) and to assess functional properties of the myocardium with cyclic variation, both at the interventricular septum (IVS) and posterior wall. Finally, we studied ventricular late potentials (VLPs) by signal-averaged electrocardiography and performed a 24-hour electrocardiography Holter monitoring to respectively define electrical instability and ventricular arrhythmias.

RESULTS

Compared with control patients, patients with HCM had, both at IVS and posterior wall, increased IB (-28.8 +/- 10 vs -35 +/- 4 dB [P =.007] and -29 +/- 8 vs -33 +/- 5 dB [P <.035], respectively) and decreased cyclic variation (6.8 +/- 2.7 vs 10.3 +/- 2.3 dB [P <.001] and 8.2 +/- 2.9 vs 11.4 +/- 2.1 dB [P <.001], respectively). In all, 5 patients with HCM had positivity of VLPs, and 4 of them showed nonsustained ventricular tachycardia (nsVT) on the Holter monitoring. Compared with patients who had HCM without VLPs and nsVT, patients with positivity of VLPs and nsVT showed higher IB both at IVS (-15.8 +/- 8.4 vs -32.6 +/- 5.9 dB [P <.001] and -16.6 +/- 9.5 vs -31.5 +/- 7.5 dB [P =.002], respectively) and at posterior wall (-19.08 +/- 8.42 vs -32.5 +/- 4.2 dB [P <.001] and -22.4 +/- 4.6 vs -31 +/- 7.5 [P =.04], respectively). A multivariate analysis showed IB at IVS (P =.042; odds ratio = 1.19) and positivity of VLPs (P =.026; odds ratio = 3.67) as independent predictors of nsVT.

CONCLUSION

Patients with HCM showed abnormal morphologic and electrical properties of the myocardium. The correlation between VLPs and IB at IVS and their relationship with nsVT suggests a link between textural and electrical nonhomogeneity of myocardial fibers, a potential substrate of nsVT in patients with HCM.

Ultrasound tissue characterization detects preclinical myocardial structural changes in children affected by Duchenne muscular dystrophy

Our goal was to identify early changes in myocardial physical properties in children with Duchenne muscular dystrophy (DMDch). Duchenne muscular dystrophy (DMD) is caused by the absence of dystrophin, which triggers complex molecular and biological events in skeletal and cardiac muscle tissues. Although about 30% of patients display overt signs of cardiomyopathy in the late stage of the disease, it is unknown whether changes in myocardial physical properties can be detected in the early (preclinical) stages of the disease. We performed an ultrasonic tissue characterization (UTC) analysis of myocardium in DMDch with normal systolic myocardial function and no signs of cardiomyopathy. Both the cyclic variation of integrated backscatter (cvIBS) and the calibrated integrated backscatter (cIBS) were assessed in 8 myocardial regions of 20 DMDch, age 7 +/- 2 years (range 4 to 10 years), and in 20 age-matched healthy controls. We found large differences in the UTC data between DMDch and controls; the mean value of cvIBS was 4.4 +/- 1.5 dB versus 8.8 +/- 0.8 dB, whereas the mean value of cIBS was 36.4 +/- 7.1 dB versus 26.9 +/- 2.0 dB (p < 10(-6) for both). In DMDch, all eight sampled segments showed cIBS mean values to be significantly higher and cvIBS mean values to be significantly lower than those in the controls. Finally, interindividual differences were greater in DMDch than in controls for both parameters.The myocardium in DMDch displays UTC features different from those in healthy controls. These results show that lack of dystrophin is commonly associated with changes in myocardial features well before the onset of changes of systolic function and overt cardiomyopathy.

Cyclic variation of myocardial integrated backscatter and myocardial wall thickness during percutaneous coronary angioplasty

Cyclic variation of myocardial integrated backscatter (CVIBS) and change in myocardial wall thickness (WT%) were evaluated during percutaneous transluminal coronary angioplasty (PTCA). Fourteen patients who underwent PTCA of the proximal left anterior descending (LAD) coronary artery were included in the study. PTCA was performed by inflating the balloon at the site of the LAD lesion for 1 minute. CVIBS was measured at three episodes during PTCA in the parasternal short-axis view: before the inflation, at the end of 1-minute inflation, and at the fifth-minute after deflation of the balloon. Three regions of interest were used to evaluate the three-vessel territories: mid-anteroseptal area for LAD, mid-posterolateral area for circumflex artery, and mid-inferior area for right coronary artery. The WT% was calculated in each area. In the LAD territory, CVIBS measured at the end of 1-minute inflation was lower than the values obtained before PTCA, 5.2 +/- 1.0 decibel (dB) versus 3.7 +/- 0.7 dB (P < 0.01). CVIBS magnitudes increased at the fifth-minute after the deflation back up even to higher levels than pre-PTCA values,6.1 +/- 1.0 dB versus 5.2 +/- 1.0 dB (P < 0.01). The WT% values decreased during balloon inflation but did not recover to the pre-inflation values measured at fifth-minute after deflation. In other sites, there was no change in either CVIBS or WT% values at any time studied. The observed increase in CVIBS may be an indicator of restoration of blood flow to ischemic myocardium.

Left ventricular remodeling, mechanics, and tissue characterization in congenital aortic stenosis

BACKGROUND

As the response of the myocardium to pressure overload is age-dependent, this study was designed to examine left ventricular (LV) remodeling, mechanics, and tissue characterization in children with moderate congenital aortic stenosis.

METHODS

We studied by echocardiography Doppler 22 patients (mean age 12.4 +/- 5.6 years) with peak and mean transvalvular gradient of 63 +/- 6 and 32 +/- 4 mm Hg, respectively. In addition, 30 age- and body surface area-matched participants with structurally normal hearts were used as a control group. Sex- and age-specific cut-off levels for LV mass/height(2.7) and relative wall thickness were defined to assess LV geometry. As a load-independent index of myocardial contractility, the relation between the rate-corrected velocity of circumferential fiber shortening both at endocardium and midwall, and meridional end-systolic stress was assessed. In addition, LV diastolic function was also evaluated by the mitral flow indexes. Finally, ultrasonic tissue characterization of the LV myocardium was performed by calculating the magnitude of cyclic variation, which reflects the intramural contractile function, and the averaged myocardial intensity of integrated backscatter, which is directly related to the myocardium collagen content.

RESULTS

The endocardial velocity of circumferential fiber shortening endocardium and meridional end-systolic stress relationship was within the normal range (mean +/- 2SD) in 18 of 22 patients (81.8%), and midwall velocity of circumferential fiber shortening at endocardium and meridional end-systolic stress was normal in all 22 patients. No mitral flow index of LV diastolic function was significantly different between aortic stenosis group and normal participants. In our study population, 16 of 22 patients (72.7%) showed normal LV geometry, 3 (13.6%) had a pattern of concentric remodeling, and 3 (13.6%) concentric hypertrophy. LV hypertrophy was not marked (left ventricular mass index [LVMI] < 51 g/m(2.7)) in any patient. Finally, compared with control participants our study population showed, both at interventricular septum and posterior wall, comparable values of cyclic variation integrated backscatter, but significantly higher values of averaged myocardial integrated backscatter intensity (P <.01).

CONCLUSIONS

In children with moderate congenital aortic stenosis, the total amount of myocardial collagen was increased despite normal LV myocardial contractility and diastolic function. Furthermore, LV remodeling was abnormal in only about a quarter of our patients and none had more than mild hypertrophy. Although the majority of these patients do not have markers now recognized to predict higher risk of cardiovascular events, the long-term significance of myocardial fibrosis and its response to treatment remain to be investigated.

Early Detection of Doxorubicin-Induced Myocardial Damage by Ultrasound Tissue Characterization With Integrated Backscatter

Doxorubicin (DXR) is one of the most effective antineoplastic agents, but its use is limited by its myocardial toxicity. Myocardial injury reduces the cyclic variation of integrated backscatter (CV-IBS) and so the present study was designed to investigate whether CV-IBS can be used to detect the early phase of myocardial damage in patients receiving DXR. Thirty-four subjects constituted the study population, none of whom showed clinically evident heart failure. CV-IBS was obtained for both the interventricular septum and the left ventricular posterior wall in the parasternal short-axis view. Standard echographic measures of left ventricular function were also made. Subjects without DXR exposure or evident cardiac diseases served as controls. The total dose of DXR administered per patient was 339+/-164 mg/m2 (range: 95-680 mg/m2). Conventional echographic parameters, including left ventricular wall thickness, dimensions, fractional shortening, and ejection fraction, showed no significant differences between the 2 groups. In contrast, CV-IBS was significantly decreased in the DXR group compared with the control group (septum: 4.7+/-1.7 vs 7.2+/-1.9 dB, p<0.0001; posterior wall: 6.7 +/-2.2 vs 8.0+/-1.6 dB, p<0.05). CV-IBS can be used as an early indicator of DXR-induced myocardial damage in patients demonstrating normal left ventricular systolic function.

Ultrasonic backscatter and diastolic function in hypertensive patients

This study was designed to assess whether ultrasonic reflectivity, evaluated by a real-time integrated backscatter analysis, was related to the severity of diastolic dysfunction, as studied by Doppler echocardiography in patients with essential hypertension. One hundred nine subjects were included in the study. Diastolic function was assessed by mitral-inflow Doppler ultrasound recordings. Backscatter cyclic variation and maximal intensity were measured in 6 regions throughout the left ventricle. The subjects were classified in 5 groups according to blood pressure and diastolic function: 29 normotensives with normal diastolic function (group 1), 18 hypertensives with normal diastolic function (group 2), 47 hypertensives with a delayed relaxation pattern (group 3), 11 hypertensives with a pseudonormal filling pattern (group 4), and 4 hypertensives with a restrictive filling pattern (group 5). The highest cyclic variation was found in groups 1 and 2, the lowest in groups 4 and 5 (5.7+/-0.2 dB in group 1 and 5.7+/-0.2 dB in group 2 versus 2.9+/-0.3 dB in group 4 and 2.1+/-0.4 dB in group 5; P<0.001), with intermediate values in group 3 (5.2+/-0.2 dB). Cyclic variation was inversely correlated with left ventricular chamber stiffness (P<0.05) and directly correlated with midwall fractional shortening (P<0.02) in all hypertensives. No differences in maximal intensity were found among the 5 groups of subjects. These results show an association between diminished cyclic variation of backscatter and deterioration of diastolic function in hypertensive patients. Thus, alterations in this parameter may be useful for the assessment of diastolic dysfunction in hypertension.

Prognostic implications derived from ultrasonic tissue characterization with myocardial integrated backscatter in patients with dilated cardiomyopathy

BACKGROUND

Various clinical parameters have been reported to predict survival in patients with dilated cardiomyopathy (DCM). Myocardial ultrasonic integrated backscatter (IB) imaging has a potential to perform in vivo tissue characterization. The present study was performed to examine whether myocardial IB analysis can predict the prognosis of DCM patients.

METHODS AND RESULTS

We prospectively carried out echocardiographic examinations with IB analysis in 43 patients with DCM (31 males, 12 females) under the standard treatment. IB analysis was performed in the left ventricular wall and the calibrated (subtracting pericardial data) myocardial IB intensity (IBI) was obtained from the interventricular septum and the left ventricular posterior wall. After the follow-up (8-39 months), 31 followed a good clinical course, but eight had cardiac death, one had partial left ventriculectomy for uncontrolled heart failure and three were hospitalized for worsening heart failure. Beta-blocker responded in 27 (87%) of the 31 with good clinical course, but it did not respond in 11 among the 12 with poor course. In these 12 DCM, left ventricular fractional shortening (LVFS) was lower (good: 18+/-5%, poor: 14+/-4, P<0.03) and calibrated IBI was higher in both the septum (good: -16.4+/-5.6 dB, poor: -11.1+/-4.2 dB, P<0.006) and the posterior wall (good: -19.5+/-3.6 dB, poor: -13.8+/-5.6 dB, P<0.004). On the Cox proportional hazard model analysis, only calibrated IBI in the septum >-17 dB, the cut-off score of calibrated IBI discriminating non-responders to beta-blocker therapy in our previous report, was related to the poor outcome (chi(2)=4.43, P=0.035). The stepwise multivariate analysis revealed that both calibrated IBI in the septum>-17 dB (chi(2)=4.43, P=0.035) and LVFS<15% (chi(2)=3.89, P=0.049) were useful to predict the poor clinical outcome. The event free rate assessed by the Kaplan-Meier method was also significantly reduced in patients with calibrated IBI in the septum >-17 dB (chi(2)=6.594, P=0.01) and calibrated IBI in the posterior wall>-17 dB (chi(2)=4.215, P=0.04). However, LVFS<15% (chi(2)=3.576, not significant) did not contribute to discriminating the event free rate in the clinical course.

CONCLUSIONS

The present study demonstrated that myocardial IB intensity was higher in DCM patients who followed a poor clinical course rather than in those with a good outcome. Therefore, it is clarified that myocardial ultrasonic tissue characterization in DCM patients is useful for assessing their clinical outcome after receiving not only the standard treatment but also beta-blocker therapy.

Ultrasonic myocardial tissue characterization in patients with hypertrophic cardiomyopathy and pressure-overloaded hypertrophy by backscattered energy temporal analysis

This study measured integrated backscatter (IB) values in the subendocardium and subepicardium of patients with hypertrophy using the newly developed Backscattered Energy Temporal Analysis (BETA) system, and evaluated the differences of acoustic properties according to etiology. Twenty-one patients with hypertrophic cardiomyopathy (HCM), 16 with pressure-overloaded hypertrophy (POH), and 21 controls were studied. M-mode formatted IB images were obtained using BETA and the region of interest (ROI), automatically divided into epicardial and endocardial halves of the myocardium, was placed in the ventricular septum and posterior wall. Values for the cyclic variation of IB (CVIB) in the entire ROI and in each half of the ROI were obtained. CVIB significantly decreased in the ventricular septum in HCM and POH compared with normal subjects, but there were no significant differences between HCM and POH. In the posterior wall, the CVIB was less in the subendocardium than in the epicardium in POH, and was also less than in normal subjects (7.0+/-1.7 dB vs 8.6+/-1.9 dB and 8.8+/-2.1 dB, p<0.05, respectively). Separate ultrasonic tissue characterization of the subendocardium and subepicardium provides further etiological information of various heart diseases.

Assessment of menopause-induced myocardial changes by integrated backscatter during inotropic stimulation and atropine injection

Estradiol has been considered as an L-type calcium channel blocker in animal studies. The concentration of estradiol decreases after menopause. Therefore, we hypothesized that human myocardial functional changes developed after menopause, and those changes could be evaluated through the use of cyclic variation of integrated backscatter (CVIBS). A total of 16 patients with menopause (native and surgical menopause), follicular stimulating hormone > 40 IU/L and estradiol < 20 pg/mL underwent dobutamine stress IBS examination (study group). Another 12 women with normal menstruation, follicular stimulating hormone < 40 IU/L and estradiol > 20 pg/mL were enrolled as a control group. All patients had a low likelihood of coronary artery disease and negative results of dobutamine stress echocardiography and (201)thallium scintigraphy. To avoid the phenomenon of anisotropy, the amplitude and phase of IBS were acquired only in the midanteroseptal segment from the parasternal short axis view. The baseline amplitudes of CVIBS differed between the control and study groups (5.9 +/- 1.2 dB vs. 8.1 +/- 2.1 dB; p = 0.007). The amplitudes during low-dose (20 microg/kg-min) and peak-dose (40 microg/kg-min) dobutamine infusion were also different between these 2 groups (5.7 +/- 0.9 dB vs. 8.4 +/- 1.7 dB; p < 0.001; 6.0 +/- 1.0 dB vs. 7.7 +/- 2.4 dB; p = 0.026). However, there were no significant differences in amplitudes between these two groups after atropine injection (control group 4.5 +/- 1.2 dB, study group 5.3 +/- 1.0 dB; p = NS). No significant differences of phase were found either at baseline or under dobutamine infusion between the two groups. Multivariate linear regression analysis showed that only menopause status associated significantly with the amplitudes at different doses of dobutamine infusion (p < 0.05). In conclusion, human myocardial functional changes are observed by CVIBS after menopause. Postmenopausal women have higher values of amplitude than premenopausal women. These phenomena persist during low and peak doses of dobutamine infusion, but are abolished by atropine injection.

Ultrasonic backscatter and serum marker of cardiac fibrosis in hypertensives

Elevations in the serum concentration of the carboxy-terminal propeptide of procollagen type I (PIP) >127 microg/L have been found to predict severe myocardial fibrosis in hypertensive patients. This study was designed to assess whether ultrasonic reflectivity, evaluated by a real-time integrated backscatter analysis, was related to the severity of myocardial fibrosis as estimated by serum PIP. Thirty-four subjects were included in the study. Serum PIP was measured by specific radio immunoanalysis. Backscatter cyclic variation and maximal intensity were measured in 6 regions throughout the left ventricle. The subjects were divided into 3 groups: 14 normotensives with PIP <127 microg/L (group 1), 12 hypertensives with PIP <127 microg/L (group 2), and 8 hypertensives with PIP >127 microg/L (group 3). The highest cyclic variation was found in group 1 and the lowest in group 3 (5.78+/-0.25 versus 4.70+/-0.33 dB, P<0.05), with intermediate values in group 2 (5.10+/-0.27 dB). No differences in maximal intensity were found among the 3 groups of subjects. Using receiver operating characteristics curves, we observed that a cutoff of 2.90 dB for cyclic variation measured in the apex provided 75% sensitivity and 63% specificity for predicting PIP >127 microg/L in hypertensives, with a relative risk of 2.50 (95% CI, 0.72 to 34.70). These results show an association between diminished cyclic variation of backscatter and increased serum concentration of PIP in hypertension. Thus, the combination of these 2 parameters may be useful for the diagnosis of severe myocardial fibrosis associated with hypertension.

Prognostic implication of myocardial texture analysis in idiopathic dilated cardiomyopathy

BACKGROUND AND AIM

Abnormal myocardial acoustic properties have been reported in patients with idiopathic dilated cardiomyopathy (IDC). The aim of this study was to investigate the relationship between quantitative ultrasonic textural alterations of myocardium and clinical outcome in IDC.

METHODS

Baseline clinical and echocardiographic variables were obtained from 28 patients with IDC. By using a videodensitometric approach, quantitative myocardial texture analysis was performed on images obtained from septum and posterior wall (PW). Cyclic variation (CV) index of mean gray level (MGL) was calculated according to the formula: (MGLdiast-MGLsyst)/MGLdiastx100. All patients were followed for an average of 11+/-5 months for the occurrence of cardiac death or repeated hospitalization due to worsening of heart failure.

RESULTS

During follow-up, 10 patients experienced cardiac events (6 cardiac deaths and 4 heart failure events). The CV indexes of both septum and PW were significantly lower in patients with cardiac events than those of event free patients (6.8+/-9.6% vs. 13.6+/-8.2%, P<0.05 and 5.3+/-6.4% vs.15.7+/-7.2% P<0.001, respectively). Univariate analysis defined the following variables as predictors of outcome: PW-CV index (chi2=13.0, P=0.0003), transmitral E/A ratio (chi2=12.5, P=0.0004), symptom status (chi2=8.7, P=0.003), and septum-CV index (chi2=4.7, P=0.03). Multivariate stepwise regression analysis showed that the PW-CV index (chi2=7.5, P=0.006) and E/A ratio (chi2=6.5, P=0.01) were the independent predictors of outcome. The event-free survival rate of patients with PW-CV index <11% was significantly lower than those with an index > or = 11 (35.7% vs. 92.8%, P=0,001).

CONCLUSION

The assessment of severely depressed CV index provides valuable prognostic information in patients with IDC.

Myocardial texture analysis in idiopathic dilated cardiomyopathy: prediction of contractile reserve on dobutamine echocardiography

Conventional resting echocardiography is not able to predict contractile reserve (CR) of patients with idiopathic dilated cardiomyopathy. The aim of this study was to investigate whether the videodensitometric myocardial texture analysis could predict the CR of these patients. Myocardial texture analysis was performed on echocardiographic digitized images of 27 patients with IDC through a calibrated 256 gray level digitization system. Cyclic variation (CV) index of myocardial mean gray level (MGL) was calculated according to the formula: (MGL(diast) - MGL(syst))/ MGL(diast) x 100. CR was defined as the %-change of ejection fraction by 10 microg/kg per minute dobutamine infusion. A clinical follow-up was also performed for all patients for an average of 8 +/- 3 months. CR ranged from -1.8% to 50.3%. CV index of both septum and posterior wall (PW) was the single parameter significantly correlated to CR (r = 0.69 and r = 0.77, respectively, P <.0001 for both). The mean resting CV index of septum and PW were significantly lower in patients with CR less than 17%-median value of all subjects-(5.7 +/- 5.6 vs 16.9 +/- 7.9 and 5.4 +/- 5.9 vs 16.1 +/- 6.4, respectively, P <.0001 for both). A CV index of 10% for both septum and PW yielded a sensitivity of 77% and 84%, and a specificity of 84% and 84% for predicting diminished CR, respectively. The event-free survival rate was significantly lower in patients with CR less than 17% (61.5% vs 92.8%, P <.05). The CV index of both septum and PW were also significantly lower in patients with cardiac events (13.6 +/- 8 vs 4.3 +/- 6, P <.05 and 14.7 +/- 7 vs 4.1 +/- 7, P <.01, respectively). Ultrasonic myocardial texture analysis in idiopathic dilated cardiomyopathy has a high ability to discriminate the patients with and without preserved CR, and patients with unfavorable outcome as well.

Stress-induced changes in subendocardial tissue texture in hypertrophic cardiomyopathy: an echocardiographic videodensitometric study

BACKGROUND

Myocardial ischemia changes myocardial acoustic properties, inducing increase of integrated backscatter and blunting of cyclic variation of backscatter. Stress-induced subendocardial underperfusion has been demonstrated in patients with hypertrophic cardiomyopathy (HCM).

AIM

To evaluate the potential of a videodensitometric approach in assessing transmural ultrasonic tissue changes in HCM during dipyridamole infusion.

METHODS

Twenty-two patients (13 males, 50+/-12 years) with HCM underwent dipyridamole echo testing (DET). Myocardial gray levels amplitude was calculated off-line on digitized images in the left subendocardial (LV-endo), right subendocardial (RV-endo) region of the interventricular septum and posterior wall (long axis parasternal view).

RESULTS

The thickness of the interventricular septum and posterior wall was 1.9+/-0.3 and 1.17+/-2.1 cm, respectively. In the LV-endo layer, the cyclic variation was blunted during DET (rest = 37+/-14 vs. DET 27+/-20%, p < 0.02). In the RV-endo layer and posterior wall, no changes occurred. In the LV-endo layer of the septum, blunting of cyclic variation was more pronounced in the 10 patients with than in the 12 without ST-segment depression during DET (21.2+/-14.7% vs. 43.8+/-15.8, p < 0.01).

CONCLUSIONS

In HCM patients, DET induced blunting of cyclic variation without the evidence of wall motion abnormalities. This reduction was more pronounced when electrocardiographic signs of ischemia were simultaneously elicited by DET.

Ultrasonic tissue characterization can predict beta-blocker efficacy in dilated cardiomyopathy

The aim was to determine if the combination of cyclic variation of myocardial integrated backscatter (variation IB) and left ventricular mass measurements can predict the efficacy of beta-blocker treatment in dilated cardiomyopathy. In 32 patients, left ventricular mass and variation IB were measured at baseline and during 6 microg/kg/min dobutamine infusion before the initiation of beta-blocker therapy. Variation IB was measured at left and right ventricular halves in the ventricular septum. The baseline left ventricular mass index and transseptal variation IB gradient during dobutamine were significantly greater in the effective group (1.16 +/- 0.18 g/mL and 1.8 +/- 0.6 dB) than in the ineffective group (0.94 +/- 0.28 g/mL, p = 0.032 and 0.4 +/- 0.6 dB, p < 0.005). When both baseline left ventricular mass index > or = 1.05 g/mL and transseptal variation IB gradient during dobutamine > or = 1.5 dB were defined as predictive criteria for the effective group, the sensitivity was 78% and the specificity was 86%. Analysis of transseptal variation IB during dobutamine may provide useful information predicting the efficacy of beta-blocker therapy in dilated cardiomyopathy.

Ultrasonic integrated backscatter in early assessment of myocardial injury during open heart surgery

OBJECTIVES

The recovery of cyclic variation of ultrasonic integrated backscatter in myocardial ischemia provides early assessment of myocardial injury and is useful in assessing myocardial injury during open heart surgery.

METHODS

We studied 25 patients with valvular disease undergoing cardiac surgery--7 with aortic stenosis, 7 with aortic regurgitation, 6 with mitral stenosis, and 5 with mitral regurgitation. All underwent transesophageal echocardiography (before aortic cross-clamping: T-pre and 60 minutes after aortic declamping: T-60). The short-axis view at the papillary muscle level of the left ventricle was recorded and anterior areas were assessed.

RESULTS

The magnitude of cyclic variation at T-pre and T-60 was 9.4 +/- 2.5 dB and 8.8 +/- 3.0 dB, and the ratio was 97 +/- 32%. Fractional shortening at T-pre and at T-60 was 27 +/- 7% and 20 +/- 9%, and the ratio was 79 +/- 44%. Recovery of magnitude was ahead of recovery of fractional shortening. The percent recovery of magnitude at T-60 did not correlate with aortic cross-clamping time (p = 0.91), postoperative peak creatine kinase-MB (p = 0.4), or catecholamine dosage (p = 0.13), but correlated with preoperative left ventricular mass index (p < 0.01). In patients with aortic stenosis, the percent recovery of magnitude at T-60 (66 +/- 4%) was significantly lower than in those with other types of valvular disease.

CONCLUSIONS

The recovery of magnitude of cyclic variation of ultrasonic integrated backscatter provides early assessment of myocardial injury, particularly in severely hypertrophied hearts, during reperfusion after aortic declamping in open heart surgery.

Echocardiographic ultrasonic tissue characterization in a case of Fabry's disease following renal transplantation

We report a case of Fabry's disease where stabilization of progressive cardiac involvement was recorded in a 29-yr-old Caucasian man, to our knowledge, for the first time by ultrasonic tissue characterization echocardiography after 1 yr of successful renal transplantation. Three echocardiographic evaluations have been made: the first 3 months before, the second 6 months after, and the third 1 yr after kidney transplantation. The myocardial structural damage - evaluated by integrated backscatter index - shows a persistence of the impairment of intrinsic myocardial contractility at septum level, probably due to coexistent hypertensive status, which is able to induce per se alterations of myocardial textural parameters. On the other hand, the cyclic variation index at posterior free wall, which is less dependent on strictly hemodynamic factors than the septum, appears quite normal at the third observation. These data could reflect the improvement of the ultrastuctural myocardial findings in relation to renal transplantation, which could correct not only renal failure but also the enzymatic deficiency by replacement of alpha-galactosidase A through the transplanted kidney.

Cyclic variation of the myocardial integrated backscatter signal in hypertensive cardiopathy: a preliminary study

BACKGROUND

Ultrasound tissue characterization studies realized through integrated backscatter analysis with end-diastolic sampling in hypertensive cardiopathy have demonstrated that abnormalities in the left ventricular myocardial ultrasonic texture are present in extreme forms of left ventricular hypertrophy (LVH). Such abnormalities are not evident in the athlete's heart. The aim of the present study was to analyze the ultrasonic backscatter myocardial indexes both as peak end-diastolic signal intensity and as cardiac-cyclic variation in two models of LVH: hypertensive cardiopathy and athlete's heart.

METHODS

Three groups of 10 subjects each, all men of mean age (31.6+/-3.5 years), and of comparable weight and height, were analyzed. Group A comprised 10 cyclists of good professional level, while hypertensive patients were grouped in Group H. Both groups presented a comparable left ventricular mass (LVM). Group C included 10 healthy subjects acting as controls. The men with hypertension were selected on the basis of the results of ambulatory monitoring of the blood pressure according to ISH-World Health Organization guidelines (International Society of Hypertension). A 2D-color Doppler echocardiography with a digital echograph Sonos 5500 (Agilent Technologies, Andover, Massachusetts, USA), was carried out on all the subjects in the study for conventional analysis of the LVM and function. The ultrasonic myocardial integrated backscatter signal (IBS) was analyzed with an 'acoustic densitometry' module implemented on a AT echograph. The signal was also sampled with a region of interest (ROI) placed at interventricular septum and at posterior left ventricular wall level. The systo-diastolic variation of the backscatter was also considered, as cyclic variation index (CVIibs).

RESULTS

According to the inclusion criteria, the LVM was comparable in groups A and H, but it was significantly higher than group C (left ventricular mass (body surface) (LVMbs)=154.5+/-18.7 (A), 146.8+/-25.5 (H), 101.4+/-12.4 (C), p < 0.001). The end-diastolic IBS did not show significant statistical differences among the three groups. The CVI(IBS) both at septum (30.5+/-5.3 (A), 13.2+/-13.1 (H), 27.2+/-7.3(C), p < 0.002) and posterior wall level (43.7+/-9.1 (A), 16.5+/-12.1 (H), 40.7+/-9.1 (C), p < 0.001) though, was significantly lower in the hypertensive patients than in both the athletes and the control group, where the results were comparable.

CONCLUSION

A significant alteration of the myocardial CVIibs (both for septum and posterior wall) was found in the hypertensive model. This was probably the expression of an alteration in the intramural myocardial function.

Prediction of contractile reserve by cyclic variation of integrated backscatter of the myocardium in patients with chronic left ventricular dysfunction

OBJECTIVE

To clarify whether assessment of the acoustic properties of the myocardium at rest can predict contractile reserve in patients with chronic left ventricular dysfunction.

METHODS

23 patients (mean (SD) age 63 (12) years) with chronic left ventricular dysfunction were studied. The magnitude of cardiac cycle dependent variation of integrated backscatter (CVIB) of the myocardium was measured at rest in the basal and mid segment of the septum and posterior wall of the left ventricle, using a real time two dimensional integrated backscatter imaging system. The results were compared with the percentage wall thickening and the wall motion at rest and during low dose dobutamine infusion. The wall motion was graded as normal, hypokinetic, or akinetic and contractile reserve was considered present when an akinetic or hypokinetic segment improved during dobutamine infusion.

RESULTS

The CVIB at rest correlated with per cent wall thickening at rest and during dobutamine infusion (at rest, r = 0.61, p < 0.0001, during dobutamine, r = 0.76, p < 0.0001). Of the 76 segments examined, 27 showed contractile reserve. The mean CVIB at rest was significantly greater in segments with contractile reserve than in those without (p < 0.0001). CVIB above 3 dB at rest predicted segments with contractile reserve with a sensitivity and specificity of 81% and 60%, respectively (p < 0.0001).

CONCLUSIONS

CVIB reflected not only myocardial contractility but also the functional capacity of the myocardium. It predicted segmental contractile reserve in patients with chronic left ventricular dysfunction.